/* ============================================
   Gapsun Website - Global Styles
   Design: Monochrome minimal, inspired by Firefox/Google
   ============================================ */

/* --- CSS Variables --- */
:root {
  /* Colors */
  --color-bg: #ffffff;
  --color-bg-secondary: #f5f5f7;
  --color-bg-tertiary: #e8e8ed;
  --color-surface: #ffffff;
  --color-surface-hover: #fafafa;
  --color-border: #d1d1d6;
  --color-border-light: #e5e5ea;
  --color-text-primary: #1d1d1f;
  --color-text-secondary: #6e6e73;
  --color-text-tertiary: #aeaeb2;
  --color-accent: #1d1d1f;
  --color-accent-hover: #48484a;
  --color-code-bg: #1d1d1f;
  --color-code-text: #e5e5ea;
  --color-success: #30d158;
  --color-warning: #ff9f0a;

  /* Gradients */
  --gradient-hero: linear-gradient(135deg, #1d1d1f 0%, #3a3a3c 50%, #636366 100%);
  --gradient-card: linear-gradient(180deg, #ffffff 0%, #f5f5f7 100%);
  --gradient-subtle: linear-gradient(135deg, #f5f5f7 0%, #e8e8ed 100%);

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  --space-4xl: 96px;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Consolas, "Courier New", monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 2.5rem;
  --font-size-4xl: 3.5rem;
  --line-height-tight: 1.25;
  --line-height-normal: 1.6;
  --line-height-relaxed: 1.8;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --max-width: 1200px;
  --nav-height: 64px;
  --content-padding: var(--space-lg);

  /* Z-index */
  --z-nav: 100;
  --z-overlay: 200;
  --z-modal: 300;
}

/* --- Page transition --- */
.page-content {
  animation: fadeInUp 0.4s ease;
}

/* --- Reset --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -moz-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

img, video, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

ul, ol {
  list-style: none;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* --- Accessibility --- */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
}

/* --- Section --- */
.section {
  padding: var(--space-4xl) 0;
}

.section--alt {
  background-color: var(--color-bg-secondary);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }

.text-secondary {
  color: var(--color-text-secondary);
}

.text-center {
  text-align: center;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--font-size-sm);
  font-weight: 500;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  white-space: nowrap;
  user-select: none;
}

.btn--primary {
  background-color: var(--color-accent);
  color: var(--color-bg);
}

.btn--primary:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn--secondary {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-primary);
}

.btn--secondary:hover {
  background-color: var(--color-border);
  transform: translateY(-1px);
}

.btn--outline {
  border: 1px solid var(--color-border);
  color: var(--color-text-primary);
  background: transparent;
}

.btn--outline:hover {
  border-color: var(--color-text-primary);
  background-color: var(--color-surface-hover);
}

.btn--small {
  padding: var(--space-xs) var(--space-md);
  font-size: var(--font-size-xs);
}

.btn--large {
  padding: var(--space-md) var(--space-xl);
  font-size: var(--font-size-base);
}

.btn--icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--radius-md);
}

/* --- Card --- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  transition: all var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-border);
}

/* --- Code Block --- */
.code-block {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  overflow-x: auto;
  line-height: 1.7;
  tab-size: 2;
}

.code-block code {
  font-family: inherit;
}

/* --- Badge --- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 10px;
  font-size: var(--font-size-xs);
  font-weight: 500;
  border-radius: var(--radius-full);
  background: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
}

.badge--success {
  background: rgba(48, 209, 88, 0.12);
  color: #30d158;
}

.badge--warning {
  background: rgba(255, 159, 10, 0.12);
  color: #ff9f0a;
}

/* --- Responsive helpers --- */
.hide-mobile {
  display: block;
}

.show-mobile {
  display: none;
}

@media (max-width: 768px) {
  :root {
    --font-size-4xl: 2rem;
    --font-size-3xl: 1.75rem;
    --font-size-2xl: 1.5rem;
    --content-padding: var(--space-md);
    --nav-height: 56px;
  }

  .section {
    padding: var(--space-3xl) 0;
  }

  .hide-mobile {
    display: none !important;
  }

  .show-mobile {
    display: block !important;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  :root {
    --font-size-4xl: 2.5rem;
    --font-size-3xl: 2rem;
    --content-padding: var(--space-lg);
  }
}

/* --- Animations --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-fade-in-up {
  animation: fadeInUp 0.6s ease forwards;
}

.animate-fade-in {
  animation: fadeIn 0.4s ease forwards;
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-tertiary);
}

/* Firefox scrollbar */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}

/* --- Page transition --- */
.page-content {
  animation: fadeInUp 0.4s ease;
}